The present invention relates to a fastening device for vehicle accessories.
Fastening devices of the above mentioned general type are known in the art. For fastening devices it is important to provide a simple assembly and disassembly and to avoid plays between the parts in the course of time. The fastening devices for automotive vehicle accessories are used for interior rearview mirrors, which are usually mounted or inserted into a support base attached to the front windshield of a vehicle. A known attachment of this type includes one support base fixed on the windshield with an adhesive, such as a glue or a double face adhesive tape and a support assembly which usually has a base attached to a support pad by a swallow tail-type fitting. An intermediate metal tube and a pivot are incorporated in the rearview mirror. The rearview mirror is also provided with an internal spring and a plastic retainer for prestressing the spheres of the base and pivoting to the opposite direction of the metal tube flanging so as to produce a torque in order to move the assembly. The thusly formed support has multiple adjustment possibilities and due to the torque it maintains the adjustment of the interior rearview mirror in a position chosen by the driver.
The above described system has been widely used since always allows a good coupling between the base and the pad and also it can be made from easily manufactured low cost parts. The swallow tail fitting system which acts between the pad and the base has been also widely used since it always allows for a good coupling between the parts, even if they have differences in dimensions or other differences due to their manufacture. Therefore the assembly is easy to manufacture and at the same time has a low cost.
The above described system has however some disadvantages. In order to maintain the pad and the base always coupled without play, a screw tightened through a threaded hole of the base and compressing against the pad is utilized. Thereby the two coupled parts are stabilized without play. The screw is usually fitted on the vehicle assembly line during the installation of the interior rearview mirror onto the windshield with the use of tools such as a pneumatic screwdriver. However, the tools are very fast and cause many screws, whose material is considerably harder than that of the base, to end up damaging the thread, harming the productivity of the assembly line and causing undesirable rejects. Besides these manufacturing problems, the known system also presents some problems during its use. Due to the car vibration, many of these screws become loose, damaging the driver's rear view. In order to solve this problem, the car owner has to tighten the screw to be able to see out of the mirror again. Another problem recognized in the above described system is that the assembly becomes too rigid and thereby all vibrations produced by the vehicle are transmitted through the windshield to the rearview mirror, harming the rear visibility.